Otrrob50

I work with otr audio files. In very many cases, the audio files I have to deal with... there is way too much bass added to the original sound recording. How do I remove the heavy bass from these recordings. I can't find any tool wave pad has to offer to remove heavy bass. The heavy bass give a muffled sound to the recording. If you don't have a tool to remove the bass can you at least develope one?